Cross-feed mechanism for machine tools



' Patented. m 16, 1922..

C. H. NORTON.

CROSS FEED MECHANISM FOR MACHINE TOOLS.

APPLICATION FILED APR. 2. I921 LEI STATES PATENT arms.

CHARLES H. NORTON, OF WORCESTER, MASSACHUSETTS, ASSIGNOR T NORTON COM- IEANY, 0F WORCESTER, MIASSIA(LIHIU'Sllii'll'l'S, A CORPORATION OF MASSACHUSETTS.

MECHANISM FOR TOOLS.

To all whom it may concern:

Be it known that 1, CHARLES H. NORTON, a citizen of the United States of America, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Cross-Feed Mechanisms for Ma-- chine Tools, of which the following is a full, clear, and exact specification.

My invention relates to a cross feed mechanism for machine tools, and more particularly to such a device adapted for use in connection with grinding machines, such as are shown for example in my copending application Serial No. 441,047 of January 29,

In the grinding of certain work, such as the pins of crankshafts, it is necessary to turn the feed wheel back a comparatively large number of revolutions, due to the usual geared-down connection of the; feed -screw to the feed wheel, in order to remove the wheel away from the work a' distance which allows the calipering of the work or the positioning of the table for grinding another pin. Since the successive pins of a crankshaft are ground to the same'diameter, it is desirable in this kind of work toha've a positive stop embodied in the cross feed construction, so that work can be rapidly and conveniently duplicated. In certain cross feed devices heretofore used, when the positive stop is in operative position it permits of only one or less than one complete revolution of the feed screw, and in consequence,

of a very small movement of the wheel slide toward the work to produce the finishing cut. When the operator wants'to move the wheel slide backward a relatively great distance for the reasons stated above or for any other reason, he will have to keep mental note of the number of times he revolves the hand wheel, and similarly, when he feeds the wheel toward the axis of the work again, he will have to rotate the feed screw the correct number of times before he throws the stop into operative position and brings the feed up to theformer position by making a partial revolution to bring it up against the stop. In rapid production work the chances of the operators count being in error are great, and if he rotates the hand wheel forwarda greater or less number of revolutions than he rotated it back, the work will'ob- Specification of Letters Patent. Patented m 1%, 1922 Application filed April 2,

192.1. Serial No. 457,929.

viously be under orover size when brought up against the stop.

It is therefore an object of my invention to overcome these difliculties. by providing a cross feed mechanism for machine tools having a positive stop, which stop is nor- -mally in inoperative position but is automatically moved to operative position, after the cross slide has been moved through the distance for which it was set, regardless of the number of revolutions of the cross feed screw or the hand wheel geared-thereto.

' It is a further object of my invention to make the means for throwing the stop into operative position'adjustable independently of the rotation of the cross feed mechanism and to lock it in adjustedposition' so that the cross feed will thereafter be stopped at the desired point.

It is a further object of my invention to provide a structure whereby the cross feed.

equipped with my automatic vstop may be operated by hand or by power.

Figure 1 is a front elevation of my improved cross feed mechanism, parts being broken away to more clearly show the construction;

Fig. 2 is a vertical transverse section therethrough approximately on the line 22 engaging it broken tion selected for illustration, I have shown the usual cross feed screw 1 mounted in the base 2 of a grinding machine. The base is provided with the usual V-way 3and 'fiat way 4 on which the work table (not shown) slides lon itudinally, and the cross feed screw mes es with the usual half nut 5 which is connected to the wheel slide (not shown) mounted to slide transversely of the base. The cross feed screw may be rotated manually from the front of the machine by means of a crank arm 6 connected to the sion of the shaft 7, bein held in place by a nut 11. .This arm is a justably connected to the shaft 7 by means of a micrometerad justing device 12 carried by an arm 13 connected to thesleeve diametrically oppo- 10 site the arm 6' and adapted to be locked in adjusted position on a toothed wheel 14 rigidly connected to the shaft as by the pins 15. The details of this micrometer ad usting device are similar to that shown in my 15 prior patent No. 762,838 dated June 14,

1904 (Fig. 12), the pinion 16 being mounted for axial movement into and out of engagement with the toothed wheel 15 and for rotation to angularly. adjust it on the wheel, a spring, pressed plunger 17 cooperating with holes 18 in an indexing plate 19 to lock the pinion in adjusted position. v

To effect the positive stop for the cross feed so as to attain the object of my invention, I may provide a stop lever having a relatively long arm 56 and a short arm 57 and being pivoted as by means of a pin 21 (Figs. 1 and 5) to the base of the machine. This lever is adapted to have a limited movement, which is preferably determinedby the width of a slot 22 in the frame, into which ,extends a short pin 23 connected to the lever, as shown in detailin Figs. 5 and 6. The lever is preferably held in inoperative position as shown in full lines in Fig. 1 by means of a spring 24 and is adapted to be moved to its operative position (shown in dotted lines in Fig. 1) after a predetermined number of revolutions of the crank arm 7 in a counterclockwise direction (Fig.1)

which is the direction for feeding the wheel slide toward the work. I

The mechanism for causing the movement of the lever to its operative position where the end of its long arm 56 lies in the path of an abutment 58 on the .arm 13 consists of a means active after a predetermined number of revolutions to engage the lever. This means may comprise a nut 20 traveling along a screw 24 and adapted to engage an arm 25 preferably forked to straddle the screw and secured to the pivot pin 21. The screw is mounted for rotation in bearing brackets 26 and 27 secured as by screws to the plate 28 carrying thecross feed mechanism The screw 24 is provided with a spiral pinion 29 keyed thereto, and this pinion meshes with a spiral gear 30 loosely mounted between a flange 31 on the spacing sleeve 32 surroundingthe shaft 7 and a short sleeve 33 surrounding the sleeve 32. The gear is rigidly connected to the arm 13 by the member 33' which is rigidly connected as by bolts to both the gear and the arm. The nut 20 is held as against rotation in a tubular member 34 by the splined connection 59, this member 34 being held at its ends in suitable bearings in the brackets 26 and 27. The bearing bracket 26 is preferably split and provided with a clamping screw 36 (Fig. 3) to rigidly clamp the member 34 in place. hen ',it is desired to move the nut 20 along the screw 21 without rotating the crank and feed screw, the clamping screw 36 is loosened and the member 34 can then be rotated. To easily effect such rotation manually, the member v34 may be provided witha knurled portion 37 I In the operation of my device, if it is desired to set-the stop mechanism so as to stop the feeding action at a predetermined point, the clamping screw 36 isloosened to allow the rotation of the tubular setting member 34, and the cross feed is operated by turning the handle 7 counterclockwise until the grinding wheel is brought up to the desired point, this being usually done by bringing the wheel up against a finished piece of work of the desired size. If the nut happens to engage the short arm 20 of the stop lever 18 before the wheel slide has moved up to this point, all the operator has to do is to rotate the member 34 in a direction to cause the nut to recede from the lever. After the wheel is in its position and the stop lever is in operative position, the pinion 16 of the micrometer adjusting device is withdrawn from the wheel 15 and the abutment 19 is moved up against the end of the stop lever and the.

pinion allowed to engage the wheel to lock the arm 13 thereto. The ratio of the gears 29 and 30 and the pitch and length of the screw 21 are such that the wheel slide can be moved. rearwardly to the limit of its movements in that direction and always be brought forward to the position for which the stop mechanism was set, so that after the operator has once set the stop at a given point, any number of duplicate pieces can be ground with a minimum of attention on his part. If the work is found to be pversize when measured after the wheel slide has been moved forward to the predetermined point, it indicates that the wheel is worn, and the operator then moves away the abutment 19 from the end of the stop lever a distance corresponding to the amount of wheel wear as determined by his measurement of the work, and then brings the work to size by again moving the abutment against the stop by rotating the handle.

In machines of this kind itis sometimes desirable to feed the wheel into the work continuously by power and I therefore provide means in my cross feed mechanism which permit me to use a power feed with my automatic stop mechanism. To accomplish this I may utilize a continuously driven shaft 38 arranged parallel to the shaft 7, and driving connections between rigidly connected. the position shown in full lines in Fig. 1,

aiaoaa chine (see Figs. 1 and a The driving con-' nections between the two shafts comprise gears 40 and 41 keyed to their respective shafts, and a tumbler gear 42 mounted in a bracket 43 (Figs. 1 and 2) adapted to be swung about the axis of the gear 4.0. The gear. 4 2 is always. in mesh with the gear 40. Bracket 43 is provided with a pin 44 (Fig. 1) adapted to be engaged by a forked member 4:5 profiecting radially from the axis of the shaft -16 to which the hand lever 39 is When the lever is .in

the gear 42 meshes with the gear atland the cross feed is operated by power. if thehand lever is thrown to the dotted line position (Fig. 1) the gears will be outof mesh and the power feed inoperative. A spring pressed latch 47 on the lever cooperates with notches 48 to normally hold the lever in' either position. The shaft 38 is driven by means of a worm wheel 49 and worm 50 from a shaft 51, which is in turn driven by any suitable means such as a sprocket gear 52 and chain 53 driven from a power shaft (not shown) in the base of the machine.

Since the power drive is connected with the stop mechanism, it is necessary to provide a yielding or slip drive to-preventbreakage of parts when the parts are brought up against the stop. Such a means may conveniently comprise a friction disk clutch mechanism 54: of known construction connecting the worm wheel 49. to the shaft 38. The driving force of the clutch can be adjusted by varying the tension of the spring 55. a 7

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

- 1. A machine tool comprising a slide, a cross feed screw for moving said slide and means for rotating said screw to move the slide rearwardly through the effective length of said screw and bring it forward again to a predetermined point. comprising a stopping device effective to limit the movement of the screw, which-is normally inoperative,

and means to render said device operative only after a predetermined forward movement of the 'slide to stop said movement.

2.- A machine tool comprising a slide, a feed screw operatively connected therewith,

'means to rotate the feed screw and move the 3. A cross feed mechanism for machine tools comprising a-cross feed screw, means for rotating. the same, an abutment on said rotating means, a stop member movable into the path of said abutment, and connections between said rotatingmeans and the stop member for moving it into the path of said abutment after a predetermined number of rotations of said means.

4. A cross feed mechanism for machine tools comprising a cross feed screw, means for rotating said screw, an abutment on said rotating means, and means for stopping said rotation at a predetermined point comprising a lever and connections between said rotating means and lever for throwing the lever into the path of said abutment.

5. A cross feed mechanism for machine tools comprising a transversely movable member, rotatable means for moving said member, an abutment on said rotatable means, a stop lever for cooperation with said abutment, and means for moving said stop lever into the path of said abutment comprising a linearly movable member driven from said rotatable 'means.

6. cross feed mechanism for machine ing said screw, and a lever operable by said I nut to move it into the path ofjsaid abutment.

7. Across feed mechanism for machine tools comprising a transversely movable ,member, a rotary means for moving said member, a continuously driven power shaft,

a device for operatively. connecting said power shaft to said means to eeifct a continuous infeed at the will of the operator, a stop to arrest the feeding movement of said member normally held in'an inoperative position, and means driven from said shaft to' move the stop to operative position, after a predetermined number of revolutions of said rotary means.

8. A cross feed mechanism for machine tools comprising a cross feed screw, power driven means for rotating said screw, means for operating the screw independently by hand, and a stopping device effective to limit the movement of the screw, which is normally inoperative, comprising means to .ren-

der said device operative only after a predetermined number of revolutions of the screw.

9-. A cross feed mechanism for machine tools comprising a cross feed screw, means for rotating said screw either manually orby power, mechanism for rendering said power feed operative or inoperative at tHe will of the operator comprising a tumbler gear and a lever at thefront of the machine operative stop device, connections between said member and the stop device for moving it to operative position in the path of said abutment and .yieldable driving connections between'said power shaft and said member,

whereby the power shaft may continue to rotate without injury to the cross feed mech anism after the abutment strikes the stop device and arrests the feeding action.

Signed at Worcester, Massachusetts, this,

31st day of March, 1921. v

. CHARLES H. NORTON. 

